Home Battery versus Generator

thebruce87m · 2025-03-22T21:17:49 1742678269

> an average home battery system costs between $10,000 to $20,000

What size is this? In the UK you can get a 16kWh LFP battery for £2,700. I believe an inverter would be £1,500.

This would cover one day of electricity usage for me if you exclude EV charging, double it to include that too. Note that my heating is gas.

I’ve considered getting a setup like this just to charge it at night at 7p/kWh and use it during the day to save paying 30p/kWh but the ROI of saving £100/month is slightly too long. If prices come down further I’ll probably bite.

TheSpiceIsLife · 2025-03-23T17:27:31 1742750851

By your numbers the payback period would be about 3.5 years. A bit more for a transfer switch and some wiring and other accessories.

That seems like reasonable investment.

dlcarrier · 2025-03-21T17:36:26 1742578586

Why not both?

Even small generators provide a lot of power at once, for a small initial price, but are expensive to run continuously. A battery has low operating cost, but one large enough to run a house off of solar power, year round, is extremely expensive. A battery that is large enough to work 99% of the time is much cheaper, and a generator can fill in that 1%, operating only a few hours a year, at a very low cost.

jareds · 2025-03-21T18:12:51 1742580771

In my case the answer to why not both was unattended reliability and piece of mind. If it's raining and we lose power we have about four hours before we start to get flooding do to a sump pump not running. Our backup generator will run a self test every week and automatically power the house with a ten second delay when the power goes out. While I suspect solar and a battery backup would keep the sump pump running for a long time it's nice to not need to choose what to run and monitor our power usage during an outage. It's also nice to not worry about power while were on vacation. With solar and a battery backup I'd be concerned about checking it while away from the house. I realize I"m somewhat of a unique situation though in just how quickly we get flooding when power goes out.

spacedcowboy · 2025-03-21T18:47:31 1742582851

I looked into getting an on-demand generator installed, but (at least in San Jose) it's just not possible within the bounds of the city. There are noise ordinances that mean your yard would have to be about 200' square, if you put the generator in the centre. And that's with the quiet ones from Generac.

Instead I went for power walls (I've had them for 8 years now, genuinely before Musk revealed himself as a Nazi), and they've proven to be a lifesaver - literally... I have an in-wall tropical fish tank, and although water will stay warm for quite a while, when it's significantly above ambient, it's going to cool down faster than you'd like.

Here, in the so-called technical Mecca of the USA, I average one power-cut per month-to-six-weeks. Most of them aren't too long (3-4 hours) but one was for 2 days or so, and all the fish would have died if we hadn't had the power walls. January-March are the worst, statistically, because apparently PG&E doesn't understand that it rains most then...

Most of the time I don't notice when there's a power cut any more, and in fact I've had the neighbours come by and ask if I still have power because they don't, and then I whip out the phone and yes, the grid is down, again. I'll generally throw an extension lead over the fence for them to use to keep the fridge powered or whatever.

pergadad · 2025-03-21T23:07:15 1742598435

Sorry to rub salt in the wound, but a power cut every month seems very high for a rich area in a rich country. Having lived decades across different cities across western Europe I've experienced power cuts maybe two or three times - and otherwise only on vacation in developing countries.

Our services here all have more or less publicly owned infrastructure with private providers handing the contracts and energy supply. I guess that must be a happy middle ground, and having a private corporation handling infrastructure seems a bad idea all around.

spacedcowboy · 2025-03-22T15:07:15 1742656035

Oh hell yes, I know it is. I moved from the UK 20 years ago. In thirty-odd years of living in the UK prior to that, I had a power cut precisely once - in the great storm of 1987 [1].

I’m leaving the US and going back to the UK in a few months - just waiting until the end of the school year for the kid’s sake. I don’t like what the USA has become, and I can retire nicely now, so it seems like a good time. I’m looking forward to not needing power-walls in the future, as well as 4 actual seasons :)

1: https://en.wikipedia.org/wiki/Great_storm_of_1987

musketeer1984 · 2025-03-21T20:45:51 1742589951

> Musk revealed himself as a Nazi

I'm assuming you're referring to the media hoax where Elon Musk was awkwardly gesturing and saying "my heart goes out to you" to a large crowd of Trump supporters after he won the election. Watch the entire clip instead of the carefully edited one that was paraded around to smear him with.

The ones acting like Nazis are the people painting swastikas on innocent people's Teslas and throwing Molotov cocktails at charging stations.

spacedcowboy · 2025-03-23T05:52:12 1742709132

There’s good folks, nazis, and nazi-sympathizers, but I repeat myself.

（评论） (comments)

（评论）
(comments)